Interference power estimation for adaptive antenna system

Abstract

There is proposed a technique for determining an estimate of interference power, in the receiver of a communication system utilizing adaptive antenna techniques. The technique uses information transmitted in the antenna signals and in the beam signals to determine the estimate of the interference power.

1. An apparatus, comprising:
 a rake receiver of a communication system having an adaptive antenna transmitter, the receiver comprising
 first input means for receiving a beam signal, 
 second input means for receiving an antenna signal, and 
 estimating means, operatively connected to the second input means, for estimating the interference power of the received beam signal for each rake finger of the rake receiver and for averaging the interference power for said rake fingers, wherein said estimating means utilises channel estimates of said antenna signal to estimate said interference power. 
 
 
   
   
     2. A method, comprising:
 receiving, by a rake receiver of a communication system having an adaptive antenna transmitter, a beam signal; 
 receiving, by the rake receiver, an antenna signal; and 
 estimating, by the rake receiver, an interference power of the received beam signal for each rake finger of the rake receiver, and averaging interference power for said rake fingers, wherein estimating of said interference power of the received beam signal utilises channel estimates of said antenna signal. 
 
   
   
     3. The method according to  claim 2 , wherein the antenna signal comprises a common pilot channel, and wherein the estimating of interference power is based on channel estimates of signals received in the common pilot. 
   
   
     4. The method according to  claim 2 , wherein the estimating is performed at the rake receiver of a cellular communication system, said cellular communication system comprising a plurality of cells, each cell comprising at least one sector. 
   
   
     5. The method according to  claim 4 , wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over a part of a sector. 
   
   
     6. The method according to  claim 2 , wherein the estimating is performed at the rake receiver of a wideband code division multiple access system. 
   
   
     7. The method according to  claim 6 , wherein the antenna signal comprises a primary common pilot channel. 
   
   
     8. The method according to  claim 6 , wherein the beam signal comprises a secondary common pilot channel. 
   
   
     9. The method according to  claim 6 , wherein the beam signal comprises a dedicated physical channel. 
   
   
     10. The method according to  claim 2 , wherein the interference power is estimated using: 
     
       
         
           
             
               
                 
                   
                     
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       where: 
       ĥ l   (c) =Channel estimate of a primary common pilot channel, 1 is path index 
       N c =Number of pilot symbols per time slot in the primary common pilot channel 
       a i   (c) =Complex pilot symbol of the primary common pilot channel, i is symbol index 
       r i,l   (c) =Received complex pilot symbol from the primary common pilot channel 
       L=Number of Paths. 
     
   
   
     11. The method as claimed in  claim 2 , wherein the estimating of interference power comprises using equal gain combining of said interference power for each rake finger. 
   
   
     12. An apparatus, comprising:
 a rake receiver of a communication system having an adaptive antenna transmitter, the receiver comprising
 a first input unit configured to receive a beam signal, 
 a second input unit configured to receive an antenna signal, and 
 an estimating unit, operatively connected to the second input unit, configured to estimate the interference power of the received beam signal for each rake finger of the rake receiver and to average the interference power for said rake fingers, wherein estimating of said interference power of the received beam signal utilises channel estimates of said antenna signal. 
 
 
   
   
     13. The apparatus according to  claim 12 , wherein the antenna signal comprises a common pilot channel. 
   
   
     14. The apparatus according to  claim 12 , wherein the beam signal comprises a dedicated channel. 
   
   
     15. The apparatus according to  claim 12 , wherein the apparatus is a part of the communication system, and
 wherein the communications system is a cellular communication system and said cellular communication system comprising a plurality of cells, each cell comprising at least one sector. 
 
   
   
     16. The apparatus according to  claim 15 , wherein the antenna signal is transmitted over an entire sector and the beam signal is transmitted over a part of a sector. 
   
   
     17. The apparatus according to  claim 12 , wherein the apparatus is part of a wideband code division multiple access system. 
   
   
     18. The apparatus according to  claim 17 , wherein the antenna signal comprises a primary common pilot channel. 
   
   
     19. The apparatus according to  claim 18 , wherein the estimation of the interference power utilises pilot signals transmitted in the primary common pilot channel. 
   
   
     20. The apparatus according to  claim 17 , wherein the beam signal comprises a secondary common pilot channel. 
   
   
     21. The apparatus according to  claim 20  wherein the estimating unit is configured to utilize pilot signals transmitted in the secondary common pilot channel. 
   
   
     22. The apparatus, according to  claim 17 , wherein the beam signal comprises a dedicated physical channel. 
   
   
     23. The apparatus according to  claim 12 , wherein the apparatus is part of a wideband code division multiple access system comprising at least one mobile station. 
   
   
     24. The apparatus as claimed in  claim 12 , wherein said estimating unit is configured to use equal gain combining of said interference power for each rake finger. 
   
   
     25. An apparatus, comprising:
 a rake receiver of a communication system having an adaptive antenna transmitter, the receiver comprising
 at least one rake finger configured to receive a beam signal, and 
 a processor configured to receive an antenna signal, 
 wherein the processor is configured to estimate the interference power of the received beam signal for each rake finger of the rake receiver and to average the interference power for said rake fingers, wherein estimating of said interference power of the received beam signal utilises channel estimates of said antenna signal. 
 
 
   
   
     26. The apparatus according to  claim 25  wherein the processor is configured to utilize pilot signals transmitted in a secondary common pilot channel. 
   
   
     27. The apparatus as claimed in  claim 25 , wherein said processor is configured to use equal gain combining of said interference power for each rake finger.